From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757104Ab3AaW1p (ORCPT ); Thu, 31 Jan 2013 17:27:45 -0500 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:50209 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756898Ab3AaW1m (ORCPT ); Thu, 31 Jan 2013 17:27:42 -0500 Message-ID: <1359671257.7527.4.camel@dabdike> Subject: Re: [PATCH 1/2] don't wait on disk to start on resume From: James Bottomley To: "dbasehore ." Cc: Sergei Shtylyov , jgarzik@pobox.com, linux-ide@vger.kernel.org, linux-kernel , linux-scsi Date: Fri, 01 Feb 2013 09:27:37 +1100 In-Reply-To: References: <1356064540-17414-1-git-send-email-dbasehore@chromium.org> <50D5C473.2030902@mvista.com> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.6.2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2013-01-31 at 14:00 -0800, dbasehore . wrote: > (Resending as plain text so the message is tracked on vger) > > Hi, thanks for reading through my patch. > > With regards to SCSI_SENSE_BUFFERSIZE, I'm following the precedent of > scsi_execute_req found in drivers/scsi/scsi_lib.c I have no context for this: I don't recall making any comment on sense buffers; what are you replying to? James > It seems that it is used by the scsi_normalize_sense function which I > call in sd_resume_async. I just input SCSI_SENSE_BUFFERSIZE directly > there though. I didn't know if anything would change its behavior on a > lower level if I made sense_len = SCSI_SENSE_BUFFERSIZE, so I just > went with what was already done. > > I'll make sure the semantic fixes go into the final patch. > > Also, I forgot to mention one possible problem earlier. I understand > that some hard drives have a command buffer that can be executed by > the hard drive in an order it determines. Does anyone know of a > potential problem if the following happens? > > -resume finishes (hard drive not started yet) > -read/write sent to disk, inserted before start command > > Could this happen? If so, could it cause any problems? > > I've tested the possibility of a program trying to read/write from the > disk before it has started, and the read/write blocks until the disk > has actually been spun up. I don't know if there are specific hard > drives where this could be a problem though. > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html